An ink jet recording apparatus has been known, which has a recording head for discharging ink as droplets onto a recording paper to print an image. The ink jet recording apparatus is provided with at least an ink container containing ink, to supply the ink from the ink container to the recording head. In an example, the recording head is provided with nozzles and an oscillation plate driven by a piezoelectric element. Making use of pressure change in the nozzles, which is caused by oscillating the oscillation plate, the ink is sucked from the ink container into the nozzles, and is discharged through ink outlets of the nozzles. Because the ink is a consumable material, the ink container is often formed as a cartridge that is removably attached to the ink jet recording apparatus, so that the ink may be supplied conveniently.
In the ink jet recording apparatus, the ink can stick to the ink outlets of the nozzles as it is dried to be viscous. Paper particles from the recording paper or dusts can also stick to the ink outlets. If the ink outlets are clogged with such obstacles, the recording head cannot discharge the ink, or ejects the ink in wrong direction. Besides that, if air bubbles enter inside the nozzles, ink discharging from the outlets becomes unstable.
To avoid these troubles, many of the ink jet recording apparatuses are provided with a capping mechanism that covers the outlets of the nozzles, as arranged on a discharging surface, with a cap while the recording head is at rest, to prevent the ink from being dried at the outlets, and/or a head cleaning device, such as a vacuum recovery mechanism that sucks viscous portions of the ink or air bubbles together with the ink out of the nozzles while covering the nozzles with a cap that is connected to a suction pump, or a wiping mechanism that wipes the obstacles like sticky ink and paper particles off the discharging surface, using an elastic wiper made of rubber or the like.
The ink sucked or wiped out of the recording head, hereinafter called waste-ink, is conventionally collected, for example through the suction pump, into a waste-ink container that is removably attached to the ink jet recording apparatus. The waste-ink container is changed with another when the waste-ink accumulated in the waste-ink container gets to a certain amount. In order to prevent spilling the waste-ink from the container as it is detached from the recording apparatus, Japanese Laid-open Patent Application No. Hei 10-244665 suggests inserting a high water absorbent polymer in the waste-ink container, so that the collected waste-ink is absorbed and coagulated by the polymer.
In order to make it easy and convenient for the user or operator to change the waste-ink container, it is desirable to form the waste-ink container as a cartridge, and insert a high water absorbent polymer or the like in the cartridge so as to prevent leakage of the waste-ink.
For the purpose of reducing load on the environment, the above-described ink cartridges are collected after use by the manufacturers, so as to recycle the containers of the used ink cartridges after disposing of the residual ink appropriately. As for the waste-ink container formed as a cartridge, hereinafter called the waste-ink cartridge, it is also desirable to collect and recycle the waste-ink cartridge after it is filled up with the waste-ink and removed from the ink jet printer. However, if the waste-ink is coagulated by the high water-absorbent polymer or the like in the waste-ink cartridge and the waste-ink cartridge has a tight case body for preventing leakage of the waste-ink, it is hard to take out the waste-ink from the waste-ink cartridge. In that case, the waste-ink cartridge must be disassembled to take out the waste-ink, which raises the requisite number of processes for recycling and thus raises the cost for recycling.